You can get another bird, you just can't assume they will get along and want to be friends. Or even that they will be civil around each other. I have some amazons that are just flat out dangerous toward other birds. I also have some that would rather fly away than get into trouble. With the more aggressive and reactive birds, you have to be willing to only have them out when other birds are not around. I think most birds like having other birds in the same room with them when they are caged. Especially if their owner works away from home. But once out of the cage, some amazons will try to expand their "territory" by flying over to another bird cage and trying to bite the occupant when they come up to investigate. Or if they are all out, an amazon might not fly over to another bird specifically intending on starting a fight, but if the other bird gets within range and fails to get out of the way fast enough, there could be blood. It just depends on the bird. This is true with any species though. I have two cockatoos and I'm careful letting them out at the same time since there is a size difference between them. My first amazon was rehomed because they were hoping she'd provide some companionship to their plucking african grey. It turned out the grey was afraid of her and she just wanted to harass him. One of the first days she was here, she flew up to my quaker cage, grabbed him by the neck and thankfully just got feathers that got pulled out when he broke away and hit the floor. She could have killed him. Needless to say, I never had the quaker and her out at the same time and always put a cover over the quaker cage if I had her out just to give myself more time to get there.
